Pond Vacuum What's A Pond Vacuum?

What's a Pond Vacuum? - pond vacuum

I asked a question about a topic that I can be dissolved dirty pond, and received a response to an empty pond ... Can someone tell me more about that? Such as:
-How does it work?

How strong / effective to solve the problem of a dirty pond in the rule

S is for algae, waste, eliminate rights?

"You can use the water is crystal clear?